JP2000221321A - Optical filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter which can be suitably used for a plasma display and which has excellent reliability by applying only a dyestuff having selective absorptivity in the visible ray region on a substantially transparent substrate. SOLUTION: A dye layer 10 is formed by applying only a dyestuff having selective absorptivity in the visible ray region on a substantially transparent substrate 20. As for the applying method of the dyestuff, a spin coating method, Langmuir-Blodgett method, vapor deposition method or the like can be used. By a spin coating method or Langmuir-Brodgett method, the dyestuff is preliminarily dissolved in a proper solvent. By a spin coating method, the solvent in which the dyestuff is dissolved is applied and then the solvent is removed in a drying process to form the dyestuff layer 10 comprising only the dyestuff molecules. Since an antireflection film 40 is laminated with an adhesive layer 30 on the dyestuff layer 10 on the glass substrate 20, the optical filter high in durability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical filter for a display, and more particularly, to an optical filter suitably used for a plasma display panel.

[0002]

2. Description of the Related Art In recent years, as society has become more sophisticated, optoelectronics-related components and equipment have remarkably advanced.
Among them, a display for displaying an image has been remarkably popular as a most important man-machine interface in multimedia, in addition to a conventional television receiver, for a computer monitor device, and the like. Among them, market demands for larger and thinner displays are increasing. 2. Description of the Related Art Recently, a plasma display panel (PDP) has attracted attention as a display that can be made large and thin. However, plasma display panels, in principle,
It is known to emit strong electromagnetic waves out of the device.
Electromagnetic waves are known to cause damage to various instruments, and it has recently been reported that electromagnetic waves may also cause damage to the human body. For this reason, the emission of electromagnetic waves is being regulated in a legal manner. For example,
At present, in Japan, we have begun to regulate electrical appliances,
unitary Control Council f
or Interference by data p
processing equipment elect
There is a regulation by the sonic office machine, and in the United States, FCC (FederalComm)
There are product regulations by the Communication Commission.

[0003] Further, since the plasma display panel uses a mixed gas of helium, xenon and neon as a discharge gas, it emits orange light having a wavelength of 590 nm. The orange light has a problem in that the purity of red is reduced and the color reproducibility of the display is reduced.

[0004]

In order to solve the above problem, it is necessary to block a specific wavelength. It is known as a band-pass filter that an inorganic thin film layer can be achieved by laminating an inorganic thin film layer, and it is known as an optical thin film (HA Macleod).
Author, Nikkan Kogyo Shimbun, 1989). A band-pass filter in which an inorganic thin film is laminated usually has 15 or more inorganic tanks laminated. For use in a large-sized display, very large equipment is required, and it is hardly industrially realistic. Actually, the aforementioned “optical thin film” on page 279 shows an example of a band-pass filter in which 20 thin film layers are stacked. Therefore, a method has been proposed in which a dye having an appropriate absorption in the visible light region is mixed into a polymer and the polymer is used (for example, Japanese Patent Publication No. 7-120515). However, each of the dyes has reactivity or the like, and there is a problem that the dye reacts with the polymer or bleeds out of the polymer after a lapse of time to precipitate. The above-mentioned polymer may be an adhesive or an adhesive, may be an extrudable thermoplastic polymer, or may be a resin for coating.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a dye can be used without being mixed with a polymer, thereby completing the present invention. Reached. That is, the present invention provides (1)
An optical filter characterized in that only a dye having selective absorption in the visible light region is applied to a substantially transparent substrate. (2) The method of applying the dye is a spin coating method, a vacuum evaporation method, a Langmuir method. The optical filter according to (1), wherein the optical filter is any of a jet jet method.
(3) The optical filter according to (1), which has an electromagnetic wave shielding ability, and (4) the electromagnetic filter exhibits an electromagnetic shielding ability by a transparent conductive layer (3).
(5) The optical filter according to (3), which exhibits an electromagnetic wave shielding function by a metal layer provided with an opening, and (6) The optical filter has near-infrared blocking ability. (7) The optical filter according to any one of (3) and (6), wherein the optical filter can be used for a plasma display.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A substantially transparent substrate which can be used in the present invention may be a glass substrate or a polymer substrate. Acrylic or polycarbonate can be typically used as the polymer substrate, but is not necessarily limited thereto. Alternatively, a laminate in which a film is bonded to a substrate can be regarded as a substantially transparent substrate. Polymer films can also be considered as transparent substrates. The transparent polymer film preferably has an appropriate heat resistance and transparency. The heat resistance is such that the glass transition temperature is at least 40 ° C. or more, and the transparency is 550 nm or more at a light transmittance of at least 80%. Preferably, there is. Specific examples of the transparent polymer film include polysulfone (PSF), polyethersulfone (PES), polyethylene terephthalate (PET), and polymethylene methacrylate (PMM).
A), polycarbonate (PC), polyetheretherketone (PEEK), polypropylene (PP), triacetylcellulose (TAC) and the like. Among them, polyethylene terephthalate (PET) is well-balanced from the viewpoint of transparency, price and heat resistance, and is particularly preferably used.

[0007] A glass plate and a polymer film, an acrylic plate and a glass plate, an acrylic plate and a polymer film, a glass plate and a polycarbonate plate, a polymer film and a polymer film, It can be easily assumed by those skilled in the art that a transparent substrate may be used for bonding.

In the present invention, the visible light region refers to a wavelength range of 380 nm to 780 nm in light wavelength, but may be considered to be substantially in a range of 400 nm to 700 nm. The dye having selective absorption in the visible light region may be a dye or a pigment, and the type thereof is not particularly limited. For example, anthraquinone type, phthalocyanine type, methine type, azomethine type, oxazine type, azo type, styryl type, coumarin type, porphyrin type, dibenzofuranone type, diketopyrrolopyrrole type, rhodamine type, xanthene type, pyromenten type And other commercially available organic dyes. The type and concentration are determined by the absorption wavelength and absorption coefficient of the dye, the color tone, and the transmission characteristics required for the display, and are not particularly limited. However, it goes without saying that durability and weather resistance required for general home appliances are required. Actually, the trade names include PS-Brilliant-Red-Hey, PS, which are available from Mitsui Chemicals, Mitsui Toatsu Dye Co., Ltd. and Mitsui Birdish Co., Ltd.
-Red-EB, PS-Brilliant-Red-
FG, PS-Red-G, PS-Brilliant-
Pink-FFR, PS-Violet-RC, MS-
Red-G, PS-Violet-RR, and the like.

As a method of applying a dye, there can be mentioned a spin coating method, a Langmuir-Blodgett method, a vacuum evaporation method and the like. In the spin coating method or the Langmuir-Blodgett method, a dye is dissolved in an appropriate solvent. In the spin coating method, after a solvent in which a dye is dissolved is applied on a substrate, the solvent in a drying step is removed to obtain a layer consisting of only dye molecules. If the desired thickness is not obtained, the desired thickness can be reached by multiple applications. In the Langmuir-Blodgett method, a dye monolayer is formed on the surface of the solvent by adjusting the surface tension of the solvent by dissolving the dye, and the layer consisting of the dye molecules is repeatedly formed by repeatedly immersing and lifting the substrate. Form on top. It is not necessary to dissolve the dye in the solvent by the vacuum evaporation method. The desired dye is set in a crucible or a Knudsen cell for vacuum evaporation and heated to a temperature at which the dye has a sufficient vapor pressure. The deposition rate depends on the temperature, but care must be taken that if the temperature is increased too much to increase the rate, the dye molecules will be broken. As another coating method, a spray method or the like can be used, but from the viewpoint of controllability of the thickness of the dye layer, a spin coating method, a vacuum evaporation method, and a Langmuir-Blodget method are preferable.

In order to obtain the electromagnetic wave shielding ability, there are a method using a layer in which a metal layer is formed in a lattice shape, and a method using a transparent conductive layer which is transparent but has conductivity over the entire main surface. . In a method using a layer in which a metal layer is formed in a lattice shape, a method of forming a metal layer on the surface of a transparent polymer film and processing the layer in a lattice shape is generally used. Alternatively, a method of knitting a conductive fiber deposited on a metal with a polymer fiber may be used. As the metal layer formed on the main surface of the transparent polymer film, those having high conductivity can be suitably used, and are not particularly limited. For example, gold, silver, copper, aluminum, There is a single metal or an alloy selected from nickel, tungsten, molybdenum, and chromium, and copper, aluminum, and nickel are particularly preferable from the viewpoint of cost and conductivity.

The thickness of the metal layer provided on the transparent polymer film is preferably from 200 nm to 2000 nm, more preferably from 200 nm to 1000 nm, further preferably from 300 nm to 700 nm. If the thickness is larger than this, there is a problem that time is required for etching. If the thickness is smaller than this, there is a problem that the electromagnetic wave shielding performance is inferior.

The aperture ratio of the light transmitting portion is 60% or more and 95%.
Or less, more preferably 65% or more and 90% or less, even more preferably 70% or more and 85% or less. The shape of the opening is not particularly limited,
Equilateral triangle, equilateral square, equilateral hexagon, circle, rectangle, rhombus,
It is preferable that the shapes are uniform and are uniformly arranged in a plane. The representative size of the opening of the light transmitting portion is preferably one side or 50 to 500 μm in diameter. If this value is too large, the electromagnetic wave shielding ability will be reduced, and if it is too small, the image will be adversely affected. In addition, the width of the metal layer where the opening is not formed is preferably 10 to 50 μm. If the width is smaller than this, processing becomes extremely difficult. On the other hand, if the width is larger than this, the image is undesirably affected.

The substantial sheet resistance of a metal layer having a light transmitting portion is defined by a four-terminal method using an electrode that is at least five times as large as the above pattern and having an electrode spacing at least five times as large as the unit of the above pattern. It refers to the measured sheet resistance. For example, when the shape of the opening is a square with a side of 100 μm and the square of the metal layer is regularly arranged with a width of 20 μm, the measurement can be performed by arranging φ1 mm electrodes at 1 mm intervals. The value measured in this way is 0.05Ω
/ □ or more and 0.5Ω / □ or less, more preferably 0.1Ω or more and 0.3Ω / □ or less. If a value smaller than this value is to be obtained, the film thickness will be too large, and it will not be possible to obtain a sufficient opening. On the other hand, if the value is larger than this, it will be impossible to obtain a sufficient electromagnetic wave shielding ability.

As a method for forming the metal layer, a vacuum process is preferably used as a method not using an adhesive. The vacuum process is a general term for a vacuum deposition method, an ion plating method, a sputtering method, and a plasma CVD method. In particular, the sputtering method is preferably used. In sputtering, the target metal solid target is bombarded with argon ions accelerated to several hundred electron volts to eject atoms from the surface of the metal solid and attach the ejected atoms to the substrate to obtain a film. .

As a method of forming the light transmitting portion, a printing method or a photoresist method can be used. In the printing method, a method of forming a pattern on a mask layer by a screen printing method using a printing resist material is generally used. In the method using a photoresist material, a roll coating method,
A photoresist material is solidly formed on the metal layer by a spin coating method, a full-surface printing method, a transfer method, or the like, and is exposed and developed using a photomask to pattern the resist. After patterning of the resist is completed, the metal portion serving as the opening is removed by wet etching, whereby a metal layer having a light transmitting portion with a desired opening shape and opening ratio can be obtained.

Furthermore, in the present invention, it is preferable to form a layer having a light reflectance of 1% or more and 50% or less on one or both surfaces of the metal layer by a vacuum process. This is because when actually used as a translucent electromagnetic wave shield, the reflection of light impairs visibility. The reflectance mentioned here is generally an average reflectance of 400 nm to 600 nm, but if there is no particular wavelength dependence of the reflectance, the wavelength is 550.
It may be represented by the reflectance of light of nm.

The layers actually formed on the metal or between the metal layer and the transparent polymer film include copper oxide, cobalt oxide, chromium oxide, molybdenum oxide,
Oxides of titanium, oxides of nickel-based alloys, oxides of tin, oxides of zinc, oxides of indium, oxides of germanium, and the like can be given. Actually, it suffices that the metal and the oxide are mixed, and it is not necessary that the oxide is completely formed. In some cases, it is preferable that the metal is mixed. The thickness of the layer for obtaining the above-mentioned reflectance of 1% to 50% does not need to be particularly thick, and is appropriately in the range of 5 nm to 100 nm. If the thickness is smaller than this, the reflectivity cannot be sufficiently reduced. If the thickness is larger than this, there is no effect of further lowering the reflectivity, but the material is wasted, and furthermore, there is a possibility that it may become an obstacle at the time of etching.

In the present invention, it is preferable that a layer having a light reflectance of 1% or more and 50% or less is formed on one or both surfaces of the metal layer by a vacuum process. It is a general term for the sputtering method, the sputtering method, and the plasma CVD method.
A sputtering method is preferably used. To select a mixed layer of a metal oxide and a metal by a sputtering method, a method of sputtering an unoxidized target in a mixed gas of argon and oxygen, a method of sputtering in a mixed gas of argon and water vapor, a method of sputtering with an argon and There is a method of performing sputtering in a mixed gas of nitrous oxide. In this case, water vapor remaining as a vacuum residual gas may be used. Alternatively, there is a method of sputtering an oxide target in an argon gas. It is easily understood by those skilled in the art that when an oxide target is used, it is effective to appropriately mix hydrogen or water vapor with argon.

The transparent polymer film has a reflectance of 1 with the metal layer.
For example, a method of forming a layer of 50% to 50% is to form a layer of 20 nm by sputtering molybdenum on a transparent polymer film in a state where oxygen or water vapor coexists, and then forming copper of 800 nm by a sputtering method. Formed and then molybdenum again in the presence of oxygen or water vapor.
By performing 0 nm sputtering, a laminate composed of a transparent polymer film / molybdenum oxide / copper / molybdenum oxide can be obtained.

The reflectance thus formed is 1 to 50.
The% layer reflectivity can be evaluated using a conventional spectrophotometer before etching. In this case, it is more preferable to use an integrating sphere than to evaluate by regular reflection. After etching and making a pattern,
From the reflectance R1 after forming the pattern, the reflectance R2 after removing the pattern, and the aperture ratio φ, R1 is simply calculated.
It can be evaluated by the formula of -R2 × (2-φ) / 2.

The composition of a layer having a reflectance of 1% to 50% is determined by a Rutherford back scattering method (RB).
S), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) can be used for the investigation using general thin film analysis methods. By these methods, it is possible to measure the mixture ratio of the oxide and the metal in this layer.

When the transparent conductive layer formed on the entire main surface is formed, the transparent conductive layer is preferably a laminate of a transparent high refractive index thin film layer and a metal thin film layer. Although a single layer of a transparent conductive thin film can provide an electromagnetic wave shielding effect to some extent, it is not sufficient, and usually a transparent high-refractive-index thin film and a metal thin film are laminated in a film thickness combination that provides sufficient transmittance and surface resistance. can get. The preferred transmittance of the transparent conductive thin film layer is 40
% Or more and 99% or less, more preferably 50% or more and 9% or less.
9% or less, more preferably 60% or more and 99% or less. Further, a preferable surface resistance value is 0.2 (Ω /
□) or more and 100 (Ω / □) or less, preferably 0.2
(Ω / □) or more and 10 (Ω / □) or less, more preferably 0.2 (Ω / □) or more and 3 (Ω / □) or less, still more preferably 0.2 (Ω / □). Above, 1.5 (Ω /
□)

A transparent conductive film laminate obtained by laminating a laminate of the transparent high refractive index thin film layer (b) and the metal thin film layer (c) on the transparent polymer molded body substrate (A). When the structure is specifically shown, A / b / c / b, A / b /
c / b / c / b, A / b / c / b / c / b / c / b, A
/ B / c / b / c / b / c / b / c / b, A / b / c /
b / c / b / c / b / c / b / c / b.

It is preferable that the material used for the transparent high-refractive-index thin film layer has as high a transparency as possible. Here, “excellent in transparency” means that when a thin film having a thickness of about 100 nm is formed, the wavelength of the thin film is 400 to 70 nm.
It indicates that the transmittance for 0 nm light is 60% or more. The high-refractive-index material is a material having a refractive index for light of 550 nm of 1.4 or more. These may be mixed with impurities depending on the application.

Examples of materials that can be suitably used for the transparent high refractive index thin film layer include oxides of indium and tin (ITO) and oxides of cadmium and tin (CT
O), aluminum oxide (Al ₂ O ₃ ), zinc oxide (Z
nO ₂ ), an oxide of zinc and aluminum (AZO),
Magnesium oxide (MgO), thorium oxide (Th
O ₂ ), tin oxide (SnO ₂ ), lanthanum oxide (LaO)
₂ ), silicon oxide (SiO ₂ ), indium oxide (I
n ₂ O _3), niobium oxide (Nb ₂ O _3), antimony oxide (Sb ₂ O _3), zirconium oxide (ZrO _2), cesium oxide (CeO _2), titanium oxide (TiO _2), bismuth oxide (BiO ₂ ). Further, a transparent high refractive index sulfide may be used. Specific examples include zinc sulfide (ZnS), cadmium sulfide (CdS), and antimony sulfide (Sb ₂ S ₃ ).

As the transparent high refractive index material, among others, IT
O, TiO ₂ , ZnO and SnO ₂ are particularly preferred. IT
O and ZnO ₂ have conductivity, and the refractive index in the visible region is as high as about 2.0, and has almost no absorption in the visible region. TiO ₂ is an insulator and has a slight absorption in the visible region, but has a large refractive index for visible light of about 2.3.

As the material of the metal thin film layer used in the present invention, a material having as high an electric conductivity as possible is preferable, and silver, gold, palladium or an alloy thereof is used. Among them, silver has a specific resistance of 1.59 × 10 ⁻⁶ (Ω ·
cm), which is the most suitable among all materials because it has the best electrical conductivity and the visible light transmittance of the thin film. However, silver has a problem that it lacks stability when formed into a thin film and is susceptible to sulfidation and chlorination. For this reason, in order to increase the stability, it is preferable to use an alloy of silver and gold or an alloy of silver and palladium instead of silver. Copper has a thin film inferior in visible light transmittance as compared with silver, but has a specific resistance of 1.67 × 10 ⁻⁶ (Ω · cm), and is extremely excellent in electrical conductivity next to silver. Therefore, it can be suitably used for the metal thin film in the present invention.
Gold also has a thin film inferior to silver in transmittance of silver like copper, but has a specific resistance of 2.35 × 10 ⁻⁶ (Ω · cm), which is superior to silver and copper in electrical conductivity. It can be suitably used as a metal thin film in the above.

The high refractive index thin film layer and the metal thin film layer may be formed by a conventionally known method such as a vacuum deposition method, an ion plating method, and a sputtering method. For forming the metal thin film layer, a vacuum evaporation method or a sputtering method is suitably used. In the vacuum evaporation method, a metal thin film can be easily formed by using a desired metal as an evaporation source and performing heating evaporation by resistance heating, electron beam heating, or the like. When a sputtering method is used, a desired metal material is used as a target, an inert gas such as argon or neon is used as a sputtering gas, and a metal thin film is formed using a DC sputtering method or a high-frequency sputtering method. Can be. In order to increase the deposition rate, a DC magnetron sputtering method or a high-frequency magnetron sputtering method is often used.

For forming the transparent conductive thin film layer, an ion plating method or a reactive sputtering method is suitably used. In the ion plating method, a desired metal or sintered body is subjected to vacuum deposition by resistance heating, electron beam heating or the like in a reactive gas plasma. In the reactive sputtering method, a desired metal or a sintered body is used as a target, and sputtering is performed using an inert gas such as argon or neon as a reactive sputtering gas. For example, I
In the case of forming a TO thin film, DC magnetron sputtering is performed in an oxygen gas using an oxide of indium and tin as a sputtering target.

Performing an antireflection treatment on the surface of the laminate on which the metal layer or the transparent conductive thin film layer is not formed is also one of the preferred embodiments of the present invention. The antireflection treatment is to form an antireflection layer on a polymer film, and the visible light reflectance of the surface on which the antireflection layer is formed is 0.1% or more and 2% or less, preferably 0.1
% And 1.5% or less, more preferably 0.1% or more and 0.5% or less. The visible light reflectance of the surface on which the anti-reflection film is formed is determined by roughening the opposite surface (the surface on which the anti-reflection film is not formed) with sandpaper and eliminating the reflection on the opposite surface by black paint to prevent reflection. It can be known by measuring reflected light generated only on the surface on which the film is formed.

As the anti-reflection layer, specifically, a fluorine-based transparent polymer resin, magnesium fluoride, or silicon-based material having a refractive index of 1.5 or less, preferably 1.4 or less in the visible light region is low. For example, 1 /
Four-wavelength optical film with a single layer, different refractive index, inorganic compounds such as metal oxides, fluorides, silicides, borides, carbide nitrides, sulfides, etc. or silicon-based resins, acrylic resins, fluorine Thin films of organic compounds such as
There are those in which a plurality of layers are laminated. What was formed as a single layer,
Although it is easy to manufacture, its antireflection property is inferior to that of a multilayer laminate. The multilayer laminate has an antireflection function over a wide wavelength range, and there is little restriction on optical design due to the optical characteristics of the base film. For the formation of these inorganic compound thin films, conventionally known methods such as sputtering, ion plating, ion beam assist, vacuum deposition, and wet coating may be used.

Applying an antiglare treatment to the surface of the laminate according to the present invention on which the metal layer is not formed is one of the preferred embodiments of the present invention. The anti-glare treatment is a treatment which is transparent to visible light having minute irregularities of about 0.1 to 10 μm on the surface. Specifically, an acrylic resin, a silicone resin, a melamine resin, a urethane resin, an alkyd resin, a thermosetting resin such as a fluororesin or a photocurable resin such as silica,
Ink particles obtained by dispersing particles of an inorganic compound or an organic compound such as melamine or acrylic are coated and cured on a transparent polymer film by a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, or the like. . The average particle size of the particles is 1 to 40 μm. Alternatively, a thermosetting or photocurable resin such as an acrylic resin, a silicon resin, a melamine resin, a urethane resin, an alkyd resin, or a fluorine resin is applied to a substrate, and a mold having a desired haze or surface state is provided. The antiglare film can also be obtained by pressing and curing. Moreover,
An antiglare film can also be obtained by treating a base film with a chemical, such as etching a glass plate with hydrofluoric acid or the like. In this case, the haze can be controlled by the processing time and the etching property of the chemical. the above,
In the anti-glare film, it is only necessary that appropriate irregularities are formed on the surface, and the production method is not limited to the method described above.

The haze of the antiglare film is 0.5% or more and 20% or less, preferably 1% or more and 10% or less.
It is as follows. If the haze is too small, the antiglare ability is insufficient, and if the haze is too large, the parallel light transmittance decreases,
The visibility deteriorates. This antiglare film can be used as an anti-Newton ring film in many cases. As the polymer film that can be used as the base material, a film having excellent transparency is suitably used. The anti-glare layer may be formed on the metal layer. In this case, the number of members can be reduced, and the manufacturing cost can be reduced in some cases. Performing the anti-reflection treatment and the anti-glare treatment at the same time is a design item that can be easily assumed by those skilled in the art.

Examples of preferable materials for use as the transparent support on which the laminate of the present invention is laminated to obtain an optical filter include acrylic resins such as polymethyl methacrylate (PMMA) and polycarbonate resins. However, it is not limited to these resins.
Among them, PMMA can be suitably used because of its high transparency in a wide wavelength region and high mechanical strength. There is no particular limitation on the thickness of the polymer molded body, as long as it has sufficient mechanical strength and rigidity to maintain flatness without sagging. Usually, it is about 1 to 10 mm.

When the transparent support is a polymer, a hard coat layer is often provided for the purpose of increasing the hardness or adhesion of the surface. As the hard coat layer material, an acrylate resin or a methacrylate resin is often used, but is not particularly limited. As a method of forming the hard coat layer, an ultraviolet curing method or a polymerization transfer method is often used, but is not particularly limited thereto. In the polymerization transfer method, the target material is
The hard coat layer can be formed with very high productivity by a continuous plate making method, although it is limited to a cell cast polymer such as a methacrylate resin. For this reason, the formation of the methacrylate resin layer by the polymerization transfer method is the most suitably used method of forming a hard coat layer.

The transparent support may have a thickness of 2 to 5 m.
m glass can also be used. When glass is used, it is preferable to perform heat treatment or chemical strengthening treatment from the viewpoint of safety. The anti-reflection treatment and the anti-glare treatment on the transparent support may be performed directly on the transparent support by the above method, or the same effect can be obtained by attaching a film subjected to the above treatment. it can. In general, a film subjected to an anti-reflection treatment is referred to as an anti-reflection film, a film subjected to an anti-glare treatment is referred to as an anti-glare film or an anti-glare film, and a surface to which these films are attached is referred to as an anti-reflection treatment surface, referred to as an anti-glare treatment. be able to.

In the present invention, the adhesive used for bonding is preferably as transparent as possible. Specific examples of usable adhesives include acrylic adhesives, silicone-based adhesives, urethane-based adhesives, polyvinyl butyral adhesives (PVB), and ethylene-vinyl acetate-based adhesives (EVA). Above all, acrylic pressure-sensitive adhesives are particularly preferably used because of their excellent transparency and heat resistance.

The forms of the pressure-sensitive adhesive and the adhesive can be roughly divided into sheet-like and liquid-like forms. The sheet-shaped pressure-sensitive adhesive is usually of a pressure-sensitive type, and is laminated by laminating each member after lamination. The liquid adhesive is cured by leaving it at room temperature or heating after application and bonding. Examples of the method of applying the adhesive include a bar coating method, a reverse coating method, a gravure coating method, and a roll coating method. Is selected in consideration of the type, viscosity, application amount, etc. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is 0.5 to 50 μm, preferably 1 to 30 μm. After bonding using an adhesive, to remove the air bubbles that entered when bonding, or to dissolve in the adhesive, and to further improve the adhesion between the members,
Curing is preferably performed under pressurized and heated conditions. At this time, the pressure condition is generally about several atmospheres to about 20 atmospheres, and the heating condition is generally room temperature or higher and 80 ° C. or lower, although it depends on the heat resistance of each member.

In the present invention, there is no particular limitation on the method of attaching the laminate to the transparent support. Normally, an adhesive is stuck to the laminate, and a layer covered with a release film is prepared in advance in the form of a roll, and while the laminate is being pulled out from the roll, the release film is peeled off, and the transparent support is provided. Paste on the body, paste while pressing with a roll. The same applies to the case where the laminated body is laminated on the laminated body.

In the optical filter according to the present invention, the inclusion of a near-infrared absorbing material in any member is one of the preferred embodiments of the present invention. Near-infrared absorbing material
A compound that absorbs light having a wavelength of 800 nm to 1000 nm. As a member that can contain a near-infrared absorbing material, for example, it can be kneaded into any polymer film. When the transparent support is a polymer, a substrate can be obtained by kneading and extruding a near-infrared absorbing material. If a transparent support is obtained by polymerizing a monomer, it is a matter of course that a near-infrared absorbing material can be added to the monomer. In addition, a person skilled in the art can easily think of including a near-infrared absorbing material in the adhesive layer.

Examples of the near-infrared absorbing material include dithiol-based complex compounds and phthalocyanine. The near-infrared absorbing material absorbs electromagnetic waves having a wavelength of 800 nm to 1000 nm, but may also absorb light in the visible region. In such a case, a dye having absorption in another visible region can be used in order to erase the color of the near-infrared absorbing material and make the color of transmitted light in the visible region neutral gray. The member containing the dye may be the same member as the near-infrared absorbing material, or may be another member.

When the transparent support is glass, colored glass may be used in place of the dye. What is colored glass?
Blue-blue-green-yellow-green colored glass containing transition metal ions such as cobalt, copper and chromium, red colored glass containing colloids such as gold and selenium, and brown colored glass containing metal sulfide colloids. No. Further, in a device requiring an electromagnetic wave shield, electromagnetic wave leakage is suppressed by providing a metal layer inside the case of the device or forming the case itself from a conductive material. In the case of a display that requires transparency, such as a display, the effect is maximized by releasing the generated electric charge to the ground after absorbing the electromagnetic wave by the electromagnetic wave shield using the laminate according to the present invention. Therefore, it is necessary that the electromagnetic wave shield is electrically connected to the inside of the display case. One of the preferred embodiments of the present invention is to provide an electrode having electrical contact with the laminate according to the present invention around the electromagnetic wave shield in order to improve the electrical contact. The electrodes provided on the peripheral portion are preferably provided continuously, but may be provided on a part of the peripheral portion.

[0043]

Next, the present invention will be described in detail with reference to examples. The present invention is not limited by the following examples. Example 1 Dye PS-Viole manufactured by Mitsui Chemicals, Inc.
t-RR was dissolved in ethyl acetate at a concentration of 12 g / l. A solvent in which the dye is dissolved is coated on a glass substrate having a thickness of 3 mm by spin coating, and then coated at 80 ° C. for 2 hours.
After drying for a time, a layer of a dye having a thickness of 120 nm was formed on the glass substrate. An antireflection film was attached to both sides of the glass substrate to obtain an optical filter. FIG. 1 shows a cross-sectional view of the configuration of the obtained optical filter.

Example 2 Dye PS manufactured by Mitsui Chemicals, Inc.
-Violet-RC and pyromethene dye (maximum absorption wavelength 497 nm) in ethyl acetate at a weight ratio of 1: 1 in 15 g
Per liter. The solvent in which this dye was dissolved was coated on a glass substrate having a thickness of 3 mm by the Langmuir-Blodgett method, and then dried at 80 ° C. for 2 hours to form a layer made of the dye having a thickness of 80 nm on the glass substrate. . A transparent conductive film consisting of a polyethylene terephthalate film (thickness: 75 μm) with a transparent conductive layer consisting of silver and indium oxide formed on the surface where the dye layer is formed, and an adhesive material on the surface where the conductive surface is not formed Pasted. An antireflection film was bonded to both principal surfaces of the thus obtained laminate having the structure of glass / dye layer / adhesive layer / polyethylene terephthalate / transparent conductive layer to obtain an optical filter. The anti-reflection film with the transparent conductive layer attached to the side is attached so that the transparent conductive layer appears in a frame shape,
A frame-shaped electrode was formed on the frame-shaped portion where the transparent conductive layer appeared by a screen printing method using a silver paste. FIG. 2 shows a cross-sectional view of the obtained optical filter.

Example 3 Dye PS manufactured by Mitsui Chemicals, Inc.
-Violet-RC and a pyromethene dye (maximum absorption wavelength 497 nm) were dissolved in methyl ethyl ketone at a concentration of 10 g / liter in a weight ratio of 1: 1.2. A solvent in which the dye is dissolved is coated on a glass substrate having a thickness of 3 mm by spin coating, and then dried at 80 ° C. for 2 hours.
A layer made of a dye having a thickness of 300 nm was formed on a glass substrate. On the surface on which the dye layer was formed, a transparent conductive layer consisting of silver and indium oxide was formed by a sputtered layer. An antireflection film was adhered to both principal surfaces of the thus obtained laminate having the structure of glass / dye layer / transparent conductive layer to obtain an optical filter. The anti-reflection film with the transparent conductive layer attached to the side is attached so that the transparent conductive layer appears in a frame shape, and the transparent conductive layer appears in a frame shape by a screen printing method using a silver paste on the frame-shaped portion where the transparent conductive layer has appeared. An electrode was formed. FIG. 3 shows a cross-sectional view of the optical filter thus obtained.

Example 4 Dye PS manufactured by Mitsui Chemicals, Inc.
-Violet-RR and near-infrared absorbing material SIR-159
(Center absorption wavelength: 850 nm) and a pyrromethene dye (maximum absorption wavelength: 497 nm) by 10
Films were formed on a glass substrate having a thickness of 3 mm in a thickness of 0 nm. Copper / line = 25 μm / 2 on the surface on which the dye layer is formed
A polyethylene terephthalate film (75 μm) having a grid shape and a thickness of 75 μm and a thickness of 1 μm was attached to the surface on which the copper layer was not formed and the surface of the dye with an adhesive. An antireflection film was adhered to both principal surfaces of the thus obtained laminated body composed of glass / dye layer / adhesive layer / polyethylene terephthalate / lattice copper layer to obtain an optical filter. The antireflection film with the copper layer attached to the side is attached so that the copper layer appears in a frame shape, and the electrodes are formed in a frame shape by a screen printing method using a silver paste on the frame portion where the transparent conductive layer appears. Formed. FIG. 4 shows a cross-sectional view of the optical filter thus obtained.

Comparative Example 1 Dye PS manufactured by Mitsui Chemicals, Inc.
-Violet-RR was mixed with a polyester-based hot melt adhesive at 1200 ppm to prepare a dye-containing adhesive. Using this dye-containing adhesive, an antireflection film was bonded to one main surface of a glass substrate having a thickness of 3 mm. An antireflection film was adhered to the main surface without the dye layer using a transparent adhesive to obtain an optical filter. FIG. 5 shows a cross-sectional view of the configuration of the obtained optical filter.

When the optical filters produced in Examples 1 to 4 and Comparative Example 1 were placed in a test container at 60 ° C. and 95% relative humidity and left for 500 hours, there was no change in Examples 1 to 4. However, in the comparative example, the color tone was uneven.

[0049]

According to the present invention, an optical filter having high durability can be obtained, and further, it can be suitably used for a plasma display by using it, and has an electromagnetic wave shielding function and a near infrared ray shielding function as required. An optical filter can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical filter according to a first embodiment.

FIG. 2 is a sectional view of an optical filter according to a second embodiment.

FIG. 3 is a sectional view of an optical filter according to a third embodiment.

FIG. 4 is a sectional view of an optical filter according to a fourth embodiment.

FIG. 5 is a sectional view of an optical filter of Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dye layer 20 Transparent substrate 30 Adhesive layer 40 Antireflection film 50 Transparent polymer film 60 Transparent conductive layer 70 Electrode 80 Lattice metal layer 90 Dye-containing adhesive layer

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuhiko Koike 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2H048 CA06 CA14 CA19 CA24 2K009 AA01 BB02 DD02 DD03 EE01 EE03 4F100 AB01 AG00 BA02 EH46 EH66 GB41 JD08 JD10 JD14B JG01 JL00 JL10B JM03 JN01A

Claims (7)

[Claims] 1. An optical filter, characterized in that a substantially transparent substrate is coated with only a dye having selective absorption in the visible light region. 2. The optical filter according to claim 1, wherein the coating method of the dye is any one of a spin coating method, a vacuum evaporation method, and a Langmuir-Blodgett method. 3. The optical filter according to claim 1, wherein the optical filter has an electromagnetic wave shielding function. 4. The optical filter according to claim 3, wherein the transparent conductive layer exhibits an electromagnetic shielding function. 5. The optical filter according to claim 3, wherein an electromagnetic wave shielding function is exhibited by a metal layer provided with an opening. 6. The optical filter according to claim 1, wherein the optical filter has a near-infrared blocking ability. 7. The optical filter according to claim 3, wherein a plasma display can be used.